I plan to use small molecules to unravel the roles of AP-1 in clathrin-mediated transport between the TGN and endosome. A rapid, reversible inhibitor of AP-1 dependant traffic will allow questions of redundancy and cooperation between AP-1 and other clathrin adaptors to be asked. Due to conservation between the yeast and mammalian trafficking pathways, inhibitors identified in yeast may prove active in mammalian cells where their utility is undeniable. In collaboration with the ICCB group at Harvard Medical School, we will identify inhibitors of AP-1 dependant traffic by screening for chemicals that inhibit growth of a sensitized strain. Preliminary hits will then undergo further rounds of screening to eliminate false positives. The target will be identified using one of several available techniques, which may include over-expression suppression or direct binding of proteins from extracts. Once identified, chemicals will be used to investigate the role of AP-1 in yeast and mammalian cells.